Apparatus for water purification



Nov. 18, 1941-. M, P, RO INSON 2,263,398

APPARATUS FOR WATER PURIFICATION INVENTOR.

M ATTORNEY.

v Patented Nov. 18, 1941 UNITED STATES PATENT OFFICE APPARATUS ron wA'rIm PURIFICATION Merrill P. Robinson, Upper Montclair, N. J. Application August 3, 1938, Serial No. 222,772

' Claims. This invention relates to an apparatus for qwater purification and is herein illustrated as embodied in water softening procedures wherein chemical reagents introduced into the water react with the impurities, largely precipitating them and sometimes destroying their ability to react undesirably with soap.

Such procedures are very old, but many difllculties have been encountered in getting rid of the precipitate in eliminating heat losses, and in cleaning filters. Some of the difliculties arise from the too rapid flow of the water from which the precipitate is settling, other difliculties arise from the need to frequently clean the sand or other material which efiects the filtering, still other difficulties arise from the highly gelatinous nature of part or all of the precipitate obtained in softening many hard waters.

It has been common to cause the chemical reactions of water softening to take place in a tank having an inverted conical bottom and to draw off the purified water through a smaller submerged cone, but it has been found .that

precipitates build up on the conical bottom and sometimes rise high enough to close the opening between the cones. Moreover, it is found that the usual flow off valve at the apex of the bottom cone does not cause a wide enough current of water within the cone to properly wash out the precipitate.

It is also found that the narrow opening between the submerged cone and the sides of the tank causes the water current to speed up at that point where it is supposed to deposit the precipitate and again speed up as it flows toward the apex of the cone, thus preventing further depositing of the precipitate except for that believed to be thrown out by the slight centrifugal action of the turning current of water where it turns at the edge of the submerged cone.

In order to avoid the disadvantages of washing 13:... filter sand or other material with cold water, hot wash water has been drawn from the settling tank and returned to the tank to settle the impurities there, thus eliminating the deterioration of the filter material due to violent changes of temperature and preventing precipitation of impurities in hard masses, but the speed of water fiow needed for washing the filter is several times as great as thespeed of flow used during normal precipitation and filtration, with the result that the returned wash water laden with impurities violently agitates the water in the tank, interferes with the normal chemical reactions and sometimes forms hard cement-like deposits throughout the apparatus and the filter. All these adverse results are aggravated by the appreciable cooling of the wash water which, therefore, when returned near the top of the tank sets up diiierential 'temperatures causing rapid passage of some of the returned water through the treating tank, and back to the According to the present invention these and other difliculties and objections are overcome and a device and process are provided which provide a slow-moving current of water during precipitation and provide substantially clean wash water for washing the sand or other filtering medium-water at the sametemperature as the water usually filtered, and the wash water is returned for reuse.

. Other features and advantages will hereinafter appear.

In the accompanying drawing:

Figur 1 is a sectional side view on the line |'l of Figure 2 of an apparatus embodying the invention.

Figure 2 is ahorizontal section on the line 22 of Figure 1.

In the form of the invention herein shown, hard water, or other liquid to be treated, flows through a pipe Ill into a tank H. shown the water entering the intake pipe I ll flows through a heater diagrammatically shown at I2, and the water level is maintained at a level indicated. by the line l3. In the form shown the tank H is circular and is divided by a partition Ha into a down flow compartment l5 and an up-flow compartment l6. In the form shown the partition or baflle Ila extends above the waterline l3 and terminates well above the bottom of the tank II which is shown as an inverted cone l1, so that water entering through the tank ll flows slowly until it passes 011 through the outflow pipe l8 near the water line I 3 shownin the center top of the up flow compartment I 6.

Water entering through the intake ll) soonencounters suitable chemicals in solution which enter the down flow compartment l5 near the water line through a chemical intake pipe I9 to which the chemicals are shown as delivered in solution from a tank 20 by a pump 2|.

The chemicals react with the impurities in the water and form a precipitate, often gelatinous, which settles on the cone I! as the inflowing current flows slowly downwardly and by a usual size of four feet or more in diameter In the form for the tank IS. The water often fiows through the tank I! at one gallon per minute.

After the precipitate has settled the outgoing water passes through the outflow pipe l3, through the wall of the tank ll, and valve 22 a layer of granular carbon or other suitable media (not shown) in which it deposits the last traces of precipitate, and then finally is discharged for use as pure water through a pipe 24 and valve 26.

Inge carbon or other filtering medium in the filter 23 is washed at intervals to remove contaminating precipitate. To effect this washing the valves 22 and 25 are closed and a pump 23 isstarted to draw water from a jacket 21 formed by an annular wall 23 around the tank so the wash water is at the same temperature as the water in the tank II; and a valve 29 between the pump and the filter is opened so that pumped wash water at a relatively high speed from the jacket 21 agitates the carbon or filter material in the filter 23, washing it and then to a filter 23 where it passes downwardly through passes of! through a pipe 30, connected through a normally closed valve 3| (now open).

The pumped water passing through the pipe 30 is shown as entering an annular pipe 3| lying near the bottom of the tank and as discharging the wash water and its entrained precipitate through bottom jets indicated by arrows 32.

The bottom of the jacket 21 is shown as part Having thus described one embodiment of the invention, what is claimed is:

1. A hot water chemical precipitating tank for softening water having a down-flow compartment and an up-fiow compartment, an annular wall surrounding said tank and forming a wash water compartment for heating, settling sediment and storage of a supply of water well adapted to backwashing a filter because of its freedom from chemicals and chemical precipitates and other turbidities, said annular wall having a sloping bottom forming a sediment collection space, said tank spaced from said sloping bottom to form an annular opening for passing sediment from the sloping bottom of the wash water settling and storage compartment into said sediment collection space, a filter for the softened water, and means for circulating settled wash water from a point near the top of the wash water compartment through said filter and thence back to a point near the bottom of the wash water compartment for settling and re-use.

2. A hot water chemical precipitating tank for softening water having a down-flow compartment and an up-fiow compartment, an annular wall surrounding said tank and forming a wash water compartment for heating, settling sediment, and

. storage of a supply of water well adapted to of the cone n and the tank wall u is shown as slightly spaced from the cone l1, to form an annular. opening so that the entrained precipitate from the wash water rolls down the cone l1, being thrown out of the jets 32 by centrifugal action since the issuing water turns upward to keep the water level uniform.

The water in the jacket is obviously at the temperature of the contents of tank so there is no chilling of the filter. Moreover, the contents of the tank remains undisturbed by the water entering through the pipe 3|, because the slightly cooler water is introduced at the bottom where it naturally remains, and, moreover is separated from the main body of reacting water by the wall of the tank I If desired the wash water laden with precipitate may be blown off through a valve 33. The precipitate in the cone l1 may be drawn of! from time to time through an apex valve 34.

,Often the tank II is closed by a welded on cover 35 extending over the wall 23, and the wall 23 is usually supported by welded brackets 36 on the tank The opening between the tank wall I and the cone |1 through which precipitate from the wash water can pass, may be closed if the blow off valve 33 is used.

Water may be admitted to the lower part of 'the jacket 21 by a valve 31.

In the form shown the lower wall of the tank II is in the form of a ring, the wall proper terminating above the pipe 3|. The ring 38 is shown as bolted to the wall thus enabling the ring to be removed and the pipe 3| altered or back-washing a filter because of its freedom from chemicals and chemical precipitates and other turbidities, said annular wall including a sloping bottom forming a sediment collection space, said tank spaced from said sloping bottom to form an annular opening to pass sediment from the wash water compartment into the sediment collection space, a filter for the softened water, means for circulating settled wash water from a point near the top of the wash water compartment through said filter and back to a point near the bottom of the wash water compartment for settling and reuse, and a conduit having a plurality of outlet openings therein for uniformly distributing the return wash water near the bottom of the wash water compartment.

3. A hot water chemical precipitating tank for softening water having a down-flow compartment and an up-fiow compartment, an annular wall surrounding said tank and forming a wash water compartment for heating, settling sediment, and storage of a supply of water well adapted to backwashing a filter because of its freedom from chemicals and chemical precipitates and other turbidities, said annular wall including a sloping bottom forming a sediment collection space, said tank spaced from said sloping bottom to form an annular opening to pass sediment from the wash water compartment into the sediment collection space, a filter for the softened water, means for circulating settled wash water from a point near the top of the wash water compartment through said filter and back to a point near the bottom of the wash water compartment for settling and reuse, and an annular conduit in said wash water compartment and provided with a plurality of openings for directing the returned wash water in downward uniformly distributed jets about the lower part of the compartment.

4. A hot water chemical precipitating tank for softening water having a down-flow compartment and an up-fiow compartment, an annular wall surrounding said tank and'forming a wash water compartment for heating, settling sediment, and storage of a supply of water well adapted to backwashing a filter because of its freedom of chemi- 68.15 and chemical precipitates and other turbidities, said annular wall including a sloping bottom forming a sediment collection space, said tank spaced from said sloping bottom to form an annular opening to passsediment from the wash water compartment into the sediment collection space, a filter for the softenedwater, means for circulating settled wash water from a point near the top of the wash water compartment through said filter and back to a point near the bottom of the wash water compartment for settling and re-use, and a conduit for discharging the return filter wash water to the wash water compartment and facilitating movement of sediment along said sloping bottom into the sediment collection space.

5. A hot water chemical precipitating tank for softening water having a down-flow compartment and an up-flow compartment, an annular wall surrounding said tank and forming a wash water compartment for heating, settling sediment, and

1 storage of a supply of water well adapted to back-washing a filter because of its freedom from chemicals and chemical precipitates and other turbidities, said annular wall including a sloping bottom forming a sediment collection space, said tank spaced from said sloping bottom to form an annular opening to pass sediment from the wash water compartment into the sediment collection MERRILL 'P. ROBINSON. 

